


Sneaky at School

by PineTrain



Category: Gravity Falls
Genre: F/M, pinecest - Freeform
Language: English
Status: Completed
Published: 2017-04-11
Updated: 2017-04-11
Packaged: 2018-10-17 20:36:18
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 981
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/10601763
Author URL: https://archiveofourown.org/users/PineTrain/pseuds/PineTrain





	

It was Mabel’s idea, but Dipper had readily agreed.

Their parents would be coming home very late due to an office Christmas party so they’d have plenty of time to get a little more rowdy in their illicit affair. Why not build up the tension beforehand to get more excited for when they were able to go all out?

As much as they often wanted to, they usually avoided touching each other on the bus ride home because of the close quarters with the other students. Today was different though and that touching was definitely going to happen, risks be damned. Mabel always was impatient though and Dipper received a text just before his math class began and he was able to check his phone.

“bathrom brk at 1:30”

He had twenty minutes to finished the test he’d told her about. Easy enough. Dipper finished in 10 and knew he’d aced it. He didn’t actually really care if he was right about that though, more interested in the what he’d be going to the next ten minutes.

He asked to go to the bathroom six minutes later so he’d have time to make it to his destination at the time Mabel had sent him. This bathroom was a little further than the nearest one, but that had been closed since yesterday due to plumbing issues. Yet as he passed the closed one, it snapped open and a hand grasped his, pulling him in.

He was surprised, but soon smiled as he understood Mabel’s plan. Not much chance of interruption in a broken bathroom. There was a split second where they gazed into each others’ eyes before the door clicked shut and their lips came together.

They embraced and held each other close as they fought to take control of the situation. Dipper’s tongue entered Mabel’s mouth just as his greater weight pressed her to the sink. His hand fell down her back in an attempt to squeeze her ass though it was stopped by the counter. He could feel her clothes slightly wettened by the small bit of water on the marble.

Grinning at that despite himself, Dipper regretted the distraction as Mabel retaliated, shoving him back into the divider between the stalls. Her tongue explored his mouth while one hand scratched through his hair and the other guided him into the last stall.

The door bounced lightly shut as Mabel spun and pulled them so her back was to the wall of the stall. Dipper followed her lead and reached his hands under her ass so she could hop and wrap her legs behind his waist. Supported by his hands and the wall, her hand trailed from his back to the button on his pants. She was stopped when he rolled his hips against hers and she broke the kiss to breath hotly against his mouth.

They glared into each other’s eyes as she returned to her task. Unbuttoning his pants, she quickly unzipped them and pulled his cock to her. It was barely even out, and Dipper felt a light pain as the fabric dragged harshly along his length while Mabel nudged her panties to the side and let herself fall onto him. The pleasure was greater though and he ignored the thought that this was supposed to be happening several hours from now.

Mabel’s hands held his shoulders as he started pumping into her, helping lift herself in time with his thrusts. Wishing he could feel her naked body on his, Dipper kissed down her neck, then came back up to reach her mouth, covering it so he could help her keep quiet.

Their lip lock started faltering when each of them began squeaking as they approached climax. Dipper decided to say ‘Fuck it’ about kissing and moved so he could stare into Mabel’s eyes as they both panted, drool dripping from both their mouths.

*WHAM*

The door to the bathroom opened and the panic in Mabel’s eyes was just the same as his. Hadn’t he come in here for a short make out session? When had this become a quickie? He’s balls deep in his sister and someone else is right fucking out there. They hadn’t even closed the stall door properly so the guy might think it was available!

Dipper slowly moved down to sit them on the toilet, Mabel on him the whole time. Hopefully his legs would be visible and the guy wouldn’t come to this stall. He and Mabel looked at each other again, formulating a better plan with just their eyes.

*PPPPTHFFFRRRFFFFRRRRTTTTT*

Saliva dripped from Mabel’s arm as she imitated a fart as hard as she possibly could against it with her mouth.

“AAAAAAAAUUUOOOOOOOOOUUUUUAAAAAAGHHHHHHH!” Dipper yelled in unison, dropping his voice a few octaves so it wasn’t obviously him.

The sound of a few steps stumbling backward was followed by what was definitely an ass hitting the floor. Wild flailing sounded until the door was flung open.

“Dude! Fucking eat better or, just, what the fuck?!!! No wonder this is fucking broken!” the poor boy called, running off.

The twins sighed together. Mabel lifted herself off, Dipper’s completely flaccid cock easily falling out of her. Boy, had that taken all the fun out of what they were doing.

Mabel unwrapped her legs, setting her feet on the ground so she could stand and they could fix their clothes.

Sitting back down on his knees, they simply looked at each other for a bit, both disappointed by the turn of events. Eventually, Mabel tilted her head to the side with a coy smile.

“You finished your test, right?”

“Uh, yeah.”

“We’re playing hooky for the rest of the day then.”

“It’s four miles home and we don’t have our bags.”

Mabel leaned in closer, teeth fully visible in her grin. “I guess we’ll just have to be sneaky around the school then.”


End file.
